[GitHub] [airflow] feluelle commented on a change in pull request #6432: [AIRFLOW-5758] Support the custom cursor classes for the PostgreSQL hook

[GitBox <gi...@apache.org>]

feluelle commented on a change in pull request #6432: [AIRFLOW-5758] Support the custom cursor classes for the PostgreSQL hook
URL: https://github.com/apache/airflow/pull/6432#discussion_r339300623
 
 

 ##########
 File path: airflow/hooks/postgres_hook.py
 ##########
 @@ -67,6 +68,13 @@ def get_conn(self):
             password=conn.password,
             dbname=self.schema or conn.schema,
             port=conn.port)
+        if conn.extra_dejson.get('cursor', False):
+            if (conn.extra_dejson['cursor']).lower() == 'dictcursor':
+                conn_args['cursor_factory'] = psycopg2.extras.DictCursor
+            elif (conn.extra_dejson['cursor']).lower() == 'realdictcursor':
+                conn_args['cursor_factory'] = psycopg2.extras.RealDictCursor
+            elif (conn.extra_dejson['cursor']).lower() == 'namedtuplecursor':
+                conn_args['cursor_factory'] = psycopg2.extras.NamedTupleCursor
 
 Review comment:
   This looks like a [factory pattern](https://en.wikipedia.org/wiki/Factory_method_pattern) can be of good use here :)
   
   ```python
   def _get_cursor(self):
       _cursor = conn.extra_dejson['cursor'].lower()
       if _cursor == 'dictcursor':
           return psycopg2.extras.DictCursor
       if _cursor == 'realdictcursor':
           return psycopg2.extras.RealDictCursor
       if _cursor == 'namedtuplecursor':
           return psycopg2.extras.NamedTupleCursor
       raise ValueError('Invalid cursor passed {}'.format(_cursor ))
   ```
   
   I also added complete validation (see the last line).
   
   WDYT?
   So after you have this factory you can just call it like that.
   ```python
   if conn.extra_dejson.get('cursor', False):
       conn_args['cursor_factory'] = self._get_cursor()
   ```

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services